Coal face support systems



y 1963 BODO-WERNER RA-rz 3,392,531

COAL FACE SUPPORT SYSTEMS Filed Dec. 9, 1965 INVEN'LOR: Bum: JMJHNER HATz.

BY 40% WW ATTYS.

United States Patent 3,392,531 COAL FACE SUPPORT SYSTEMS Bode-Werner Riitz, 343 Frankenstrasse, Essen-Stadtwald, Germany Filed Dec. 9, 1965, Ser. No. 512,650 Claims priority, application Germany, Dec. 10, 1964,

79,681 8 Claims. (CI. 61-45) ABSTRACT OF THE DISCLOSURE An automatic control circuit for individual support units within groups of support units in a coal face support system. Each support unit has a first feeler device for sensing the coal face. The individual first feeler devices of successive units in a group are serially connected to an electric, pneumatic orhydraulic power line. If the first feeler device on any unit fails to sence the coal face, the serial connection to the following unit is broken and the power is diverted to the advance circuit of that unit. Second and third feeler devices are connected in each unit between the first feeler device and the unit advance circuit such that, when the advance drive is exhausted or the path of advance is obstructed by the conveyor, power is diverted from the unit advance circuit to the serially connected first feeler devices of the following units. Thus, the power line is connected on a priority basis to the advance circuit of the first unit in the group which fails to sense either the coal face, an obstruction to the advance of that unit, or that the unit advance drive is exhausted. This unit is then advanced in a conventional manner util either the first feeler device contacts the coal face, the second feeler device contacts an obstruction blocking the advance, or the third feeler device senses that the advance drive is exhausted.

Background of the invention This invention relates to a method and apparatus for supporting a coal-face and, more particularly to a method and apparatus for advancing support units in a hydraulic coal-face support system which has a group of automatically advancing support units.

It would be possible to effect automatically the successive advance of individual support units of a coal-face support system by connecting such units together in groups in such a manner that one support unit at a time is relieved from its bracing position and is subjected to an advancing pressure exerted by an associated advancing device which urges it to re-establish contact with the coal-face. After traveling the stepping distance, which is limited by the stroke-length of the advancing cylinder of the advancing device, this support unit actuated a control signal to return it to the bracing position and, at the same time, to initiate the release of bracing and the advance of an adjacent support unit.

According to this proposal, the support units following one after the other in the group are necessarily advanced in a stepped sequence of adjacent units. The progress of the advancing operation from one support unit to the adjacent support unit is interrupted or blocked if the bracing-relieved unit, which is subjected to the advancing pressure of the advancing device, is stopped prematurely for any reason before the initiating pulse for the next unit is released. For examples, such a blockage occurs if the bracing-relieved unit comes to a stop because its roof bar strikes an uneven part of the roof or if the distance through which its advancing cylinder can be extended is exhausted before the necessary stepping distance has been covered.

3,392,531 Patented July 16, 1968 The present invention eliminates the drawbacks and difficulties of such a system. It eliminates the stopping or blocking of the advancing operation of the group of support units in the event that the controlling unit, which releases the initiating pulse or pulse for the next advancing unit, comes to a premature stop.

Summary of the invention According to the present invention, each support unit in the group is equipped with a feeler device or switch which is actuated by abutment against the coal-face. The feeler devices may be of the type disclosed in Patent No. 3,348,381. The feeler devices of all of the support units of the group are so connected in series that the actuation of the feeler device of the first actuated one of the support units, not only initiates the advance of this first unit, but also interrupts the clear switching path to the following support units, i.e. the subsequently connected units of the group, until the advance of the first support unit is either terminated by the coal-face being reached or is prematurely stopped. When the advance of the first unit is terminated either by reaching the coal-face or by a premature stoppage, the switching path to the following support units is again cleared and the advancing process can be repeated with any one of the following units or of a preceding unit, as soon as the coal-face has been exposed in front of such unit. Thus, the switching path is normally clear from the first to the last unit in the group, but a released unit blocks the switching path to the units following it by the initiation of its own advancing operation.

It is the primary object of the present invention to provide a method and apparatus for automatically advancing the individual support units a of a plurality of support units of a coal-face hydraulic support system which are combined into a group. Instead of advancing the individual support units in a sequence progressing from unit to adjacent unit and irrespective of whether or not the operation of advancing a preceding unit is prematurely interrupted, this invention makes it possible to advance each individual support unit immediately whenever the coal-face in front of the relevant support unit is exposed, and thereby to ensure that the individual support units in the group irrespective of their sequence in the group, are always advanced when the coal-face has been exposed in front of them. nI other words, the basic idea of the invention is in causing at any given time each frame to advance when the adjacent coal-face has been exposed and, in practice, the conveyor has been advanced, provided that its advancing cylinder is not yet fully extended.

Another object of the present invention is to ensure that the advancing operation will take place even if a unit is prematurely stopped or blocked. Besides the front feeler switch, each of the units has its own control apparatus and is equipped with feeler switches, namely at the base of the front prop of the support unit and also on the advancing cylinder, the first of which prevents the prop being advanced into abutment with the conveyor and the second of which operates when the distance, by which the advancing cylinder can be extended, is exhausted. These further switches are so connected together with the control apparatus associated with each support unit that, because of the operation of one or the other of these switches and connecting circuitry stoppage of the entire advancing op eration of the group does not occur. If the switching path from the first-mentioned feeler device, conveniently a feeler switch on the roof-bar, to the control apparatus is interrupted, at the same time the switching path to the following support units may be cleared by way of the corresponding further switches. For eaxmple, if the roof-bar feeler switch strikes against an uneven part of the roof or if the abutment of the front prop of the frame strikes against the convenor or if the exhaustion of the distance by stopping of the entire advancing operation of the group does not occur, as would be the case with the prior proposal, and each and any of the roof-bar feeler switches which is released can initiate the operation of advance of its support unit.

A further object of the present invention is to provide a new method and apparatus which can be applied to units composed both of single frames and of double frames combined to form frame assemblies and also of support trestles ,the arrangement being simplified in the latter case in that the feeler switch at the prop may be eliminated.

The invention is described in detail hereinafter with reference to one embodiment wherein the invention is applied to a support system having double frames combined to form frame assemblies and to the drawing:

Brief description of the drawing FIG. 1 is a plan view of a group of double frames in use at the coal-face according to the present invention, and

FIG. 2 is a diagrammatic view of the circuit arrangement used in FIG. 1, namely, the switching devices and the switching paths which are present during the various possible stages of advance of the individual support units.

Description of the preferred embodiment In the drawings, the reference numbers 11 to 19 indicate nine double frame support units combined into a group. Naturally, the number of frames is selected as desired with the maximum possible number in the group being limited only in that lagging behind of the last frame of the group must be prevented. This could occur in a large group if the frames disposed in front of it, in the circuit, are able to operate in a privileged fashion under certain circumstances.

The drawing moreover shows, solely for the purpose of illustration, different relative positions of the frames with respect to the conveyor and to advancing cylinders during use.

The reference numbers 1', 1", 2, 2", 3' 3", etc. designates the frames combined in each case to form double frame assemblies in the group of frames.

Each individual frame 1'-3", etc., has on its roof-bar a hydraulically operated front prop 20, a hydraulically operated rear prop 21, and, at the end nearer the coal-face, a roof-bar feeler switch 4 which is a simple contact or abutment switch. Moreover, a prop-base feeler switch 5 is positioned at the base of the front prop 20 of each frame and advancing cylinder feeler switches 7', 7" are arranged on an advancing cylinder 6 of each double frame assembly.

A control apparatus 8 of conventional kind is assoicated with each of the individual frames (see FIG. 2).

The possible switching paths which are available can be seen in FIG. 2. All of the roof-bar feeler switches 4 of the individual frames are connected in series through a main lead '9. Lines 22, 23 and 24 in each frame connect the prop-base feeler switch 5 and the advancing cylinder feeler switch 7 or 7" for that frame in series between the frames roof-bar feeler switch 4 and the frames control apparatus 8. Each prop-base feeler switch 5 is also connected through a line 25 to the roof-bar feeler switch 4 of the following frame, such that the clear circuit path to the following frame is maintained when the prop-base feeler switch 5 senses an obstruction such as conveyor 10. In FIG. 2, the advancing cylinder switches 7' and 7" for each double frame assembly in FIG. 1 are generally designate dby the reference number 7. Similarly, each advancing cylinder feeler switch 7 is connected through a line 26 to the roof-bar feeler switch 4 of the following frame such that the clear circuit path to the following frame is maintained when the advancing cylinder feeler switch 7 senses hat the advancing cylinder 6 has reached the end of its rive.

When the roof-bar feeler switch 4 of any one of the frames, which are shown in FIG. 1 in various positions with respect to the coal-face, is released, the clear switching path through the roof-bar feeler switch 4 to the following support units is thereby interrupted. This interruption continues until the advancing operation, which has been initiated by the release of this feeler switch, is completed, preferably owing to the fact that the roof-bar feeler switch 4 again is brought into abutment with the coal-face, whereupon the switching path to the following support units is again cleared.

If, during this advancing operation, the roof-bar feeler switch 4 operates due to an uneven roof or the prop-base feeler switch 5 operates owing to the fact that it strikes against a conveyor 10, the advancing action of the frame is interrupted and at the same time the switching path to the next frame or all the following frames in the group is thereby cleared, so that the process can now be performed in any one of the following frames as soon as it becomes free from the coal-face.

The same event occurs when the advancing cylinder feeler switch 7' or 7" operates on full extension of the piston of the advancing cylinder.

Referring to FIG. 2, the clear circuit path for the group arrangement of FIG. 1 is shown as a solid line. The electric, pneumatic, or hydraulic power line 9 is connected to frame 13 through the roof-bar feeler switches 4 of frames 11 and 12 because the coal-face 30' is sensed by the switches. The power line is connected in frame 13 through line 22 to the prop-base feeler switch 5, because the roofbar feeler switch 4 for frame 13 does not sense the coalface 30. However, since the prop-base feeler switch 5 for frame 13 is sensing conveyor 10, line 25 maintains the clear circuit path to frame 14. As with frame 13, lines 22 and 25 in frame 14 maintain a clear circuit path to frame 15 because roof-bar feeler switch 4 for frame 14 does not sense the coal-face 30 while the prop-base feeler switch 5 senses the conveyor 10. In frame 15, roof-bar feeler switch 4 does not sense the coal-face 30, the prop-base feeler switch 5 does not sense the conveyor 10, and the advancing cylinder feeler switch 7 does not sense that the advancing drive has been exhausted. Therefore, lines 22, 23 and 24 in frame 15 connect the power line 9 to the control apparatus 8 for frame 15. Frame 15 is now advanced in a conventional manner and the circuit path to the following units 16-19 is broken until one of the feeler switches 4, 5 or 7 in frame 15 is actuated.

It will thus be appreciated that the difliculties set out at the beginning of this specification, and which arise owing to the fact that the advancing action of the entire group comes to a stop if the advancing movement of any one frame is terminated prematurely, are eliminated by the above described method and apparatus in a most simple manner.

I claim:

1. In a hydraulic coal-face support system, apparatus for effecting the automatic advance of the individual units of a plurality of support units forming a group thereof, comprising a first feeler device carried by each support unit of the group and for engagement with the coal-face, means for connecting such first feeler devices in series, means whereby the actuation of any one of such feeler devices, caused by disengagement thereof from the coalface, generates a control pulse for initiating the advance of the support unit associated with such device, circuit means normally maintaining a clear circuit path to all successive first feeler devices of the group of support units, said circuit means being so connected to the first feeler devices such that the clear circuit path to the following first feeler devices is interrupted when any one support unit of the group is advancing following initiation of such advance by actuation of its first feeler device, and switching means which, in combination with said first feeler devices, acts to clear the circuit path to the first feeler devices of the following units whenever the advance of any advancing support unit is prematurely blocked.

2. Apparatus as claimed in claim 1, wherein the switching means comprises at least one second feeler device for each support unit and which is actuable in the event of premature blocking of the advance of any unit before the first feeler device of such unit re-engages the coal-face, and wherein said circuit means is so connected to said second feeler devices such that the circuit path to the first feeler devices of the following units is cleared when the advance of any unit is prematurely stopped by actuation of its second feeler device.

3. Apparatus as claimed in claim 1, wherein said switching means comprises two further feeler devices for each support unit, each for actuation in the event of premature stopping of the advance of any unit before the first feeler device of such unit re-engages the coal-face, means for mounting one of the further feeler devices for actuation in the event of the unit advancing into contact with an obstruction, means for mounting the other further feeler device for actuation in the event of premature exhaustion of the advancing drive, and wherein said circuit means is connected to said further feeler devices such that the circuit path to the first feeler devices of the following units is cleared when the advance of any unit is prematurely stopped by the actuation of either one of its further feeler devices.

4. In a hydraulic coal-face support system, apparatus comprising: a plurality of coal-face support units forming a group thereof, bracing means for each unit enabling it to support a roof portion adjacent the coal-face, a first feeler device at the front of each unit and for contact with the coal-face, means for attaching the feeler device to the unit for actuation on disengagement thereof from the coal-face, control means for releasing a pulse when the first feeler device is actuated, means responsive to the pulse to relieve the associated support unit of its bracing, hydraulic means for advancing each support unit, switching means for controlling said hydraulic means, said switching means being responsive to said pulse to switch the hydraulic means into operation to effect advance of the associated support unit, circuit means normally maintaining a clear circuit path to all the successive first feeler devices within the group of support units, said circuit means being so connected to the first feeler devices such that the clear circuit path to the following feeler devices is interrupted when any one support unit of the group is advancing following initiation of such advance by actuation of its first feeler device, and further switching means which, in combination with the first feeler devices, acts to clear the circuit path to the first feeler devices of the following units whenever the advance of any advancing unit is stopped.

5. Apparatus as claimed in claim 4, wherein the further switching means comprises two further feeler devices for each support unit, each for actuation in the event of premature stopping of the advance of any unit before the first feeler device of such unit re-engages the coal-face, means for mounting one of the further feeler devices for actuation in the event of the unit advancing into contact with an obstruction other than the coal-face, means for mounting the other of said further feeler devices for actuation in the event of premature exhaustion of the advancing drive for such unit, and wherein the circuit means is so connected to such further feeler devices that the circuit path to the first feeler devices of the following units is cleared when the advance of any unit is prematurely stopped by the actuation of either one of its further feeler devices.

6. Apparatus as claimed in claim 5, wherein the control means comprises a power source leading to the first feeler devices of the group in succession, a transmission circuit leading from each first feeler device to the bracing means and to the switching means for the hydraulic advancing means, circuit means connecting the further feeler devices associated with each unit in series in said transmission circuit, and circuit means connecting each further feeler device associated with one unit to the first feeler device of the following unit.

7. Apparatus as claimed in claim 4, wherein the further switching means comprises at least one further feeler device for each support unit and which is actuable in the event of premature stopping of the advance of any unit before the first feeler device of such unit re-engages the coal-face, and the circuit means is so connected to such further feeler devices that the circuit path to the first feeler devices of the following units is cleared when the advance of any unit is prematurely stopped thereby causing actuation of its further feeler device.

8. A method of automatically advancing the individual support units of a plurality of support units in a hydraulic coal-face support system which are combined to form a group, wherein a control pulse, for producing the start of the process of load relief, advance and re-setting of each individual support unit, is transmitted to a unit due to the release of a feeler device for such unit which seeks to maintain contact between such unit and the coal-face, said feeler devices of all the support units in the group being connected in series in such a manner that the release from the coal-face of the feeler device of any one of the support units initiates the advancing action of such support unit and interrupts the connection to the following sup port units in the group until such advancing unit comes to a stop against the coalface and the connection to the following support units is then again cleared.

References (Iited UNITED STATES PATENTS 3,243,964 4/1966 Thomas et al 6145.2 3,248,885 5/1966 Bolton et al a- 6145.2 3,285,015 11/1966 Carnegie et al 61-45.2 3,306,050 2/1967 Andrews et al 6145.2 3,309,880 3/1967 Potts et al 61-452 DAVID J. WILLIAMOWSKY, Primary Examiner. DENNIS L. TAYLOR, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,392,531 July 16, 1968 Bodo-Werner Ratz It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 33, "util" should read until line 55, "actuated" should read actuates Column 2, line 34, cancel "a", first occurrence; line 47, "111" should read In Column 3, line 3, after "by" insert which the advancing cylinder can be extended is reached, lines 42 and 43, "designates" should read designate lines 68 and 69, "designate dby" should read designated by Column 6, line 31, beginning with "8. A method of" cancel all to and including "units is then again cleared) in line 47, same column 6. In the heading to the printed specification, line 8, "8 Claims." should read 7 Claims. Signed and sealed this 30th day of December 1969.

Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

